In recent years, miniaturization of 45-nm devices and semiconductors are advanced, so that distance and height between contacts of transistor become very short. Accordingly, when semiconductor is inspected by the device as described in Patent Literature 1, it is getting difficult to get accurate transistor characteristics because of effects of electron beams absorbed by semiconductor.
Accordingly, in the pre-processing of semiconductor, oxide layer is left as large as possible so as to make the oxide layer thicker, so that semiconductor is processed to escape from the effects of electron beams even a little. Further, acceleration voltage of electron beams and emission current are reduced to thereby decrease the effects of electron beams although there is obtained an image having low contrast and difficult to understand.